Airborne asbestos contamination in buildings is a significant environmental problem. Various diseases have been linked with industrial exposure to airborne asbestos, and the extensive use of asbestos products in buildings has raised concerns about exposure to asbestos in nonindustrial settings. Surveys conducted by the Environmental Protection Agency (EPA) estimate that asbestos containing materials can be found in approximately 31,000 schools and 733,000 other public and commercial buildings in this country.
In an effort to avoid the hazards associated with exposure to airborne asbestos, abatement actions or procedures are being extensively conducted and the Environmental Protection Agency has published a booklet entitled "Guidance for Controlling Asbestos-Containing Materials in Building". During the abatement action, several air sampling units are positioned throughout the work site to monitor the level of the airborne asbestos materials. Sampling for asbestos consists of collecting fibers by drawing air through a filter at a known rate. Usually, sampling equipment is placed at a fixed location for a certain period of time. Standard sampling equipment consists of a pump (operated at a two to twelve liter per minute flow rate), a filter in a cassette and associated tubing and supports. During the abatement action, the pumps frequently become exteriorly contaminated with the asbestos material. AFter the abatement action has been completed and the work site has been properly cleaned, sampling equipment is used to sample the air in the clean work site. Frequently, the same sampling equipment used during the abatement action is used for the final air sample. Because the sampling equipment is contaminated itself with asbestos material, the final air sample may be inaccurate since the contamination on the sampling unit itself may be drawn into the filter. This is especially true when a short length of tubing is employed between the pump and the filter since the vibration of the pump, when operated, will loosen the contamination on the pump and the same may possibly be drawn into the filter.
Further, during the final air sampling operation, the EPA recommends that "aggressive sampling" be utilized during the post-abatement air test. An aggressive sampling method involves using forced-air equipment such as a leaf blower to dislodge free fibers, then using slow-speed fans to keep the fibers suspended during sampling. The problem connected with such a procedure is that the leaf blower itself is very likely contaminated through use at other work sites and the use of the contaminated leaf blower will give rise to inaccurate samples.
It is therefore a principal object of the invention to provide a self-contained air monitoring unit.
A further object of the invention is to provide a self-contained air monitoring unit having the capability to agitate the air within a work site.
A further object of the invention is to provide an air monitoring unit wherein the air pumps are not contaminated during the monitoring procedure.
Still another object of the invention is to provide an air monitoring unit including a cabinet having a plurality of air pumps mounted therein with the air pumps only being subjected to filtered air so as to remain contaminant-free.
Yet another object of the invention is to provide an air monitoring unit which is easy to operate and which has controls associated therewith so that all of the air pumps may be activated in a substantially simultaneous fashion.
Further, it is a principal object of this invention to provide an air monitoring unit having a filter air discharge associated therewith which may be used during aggressive sampling procedures.
These and other objects will be apparent to those skilled in the art.